Phenom II: AMD pulls closer

The release of AMD's Phenom X4 quad-core processors in November of 2007 met
with very little fanfare. Intel had been first to market with their Core 2 Quad
CPUs a full 10 months earlier, and despite those extra months, AMD only managed
to squeeze 2.3GHz out of their fastest X4 chip at the time, the X4 9600. The
X4 9600 also performed rather poorly compared to the venerable Intel Core 2
Quad Q6600, despite only a small difference in clock speed (100MHz). It was
also very power inefficient.

At the time, many people questioned whether anyone need four cores, since most
applications didn't perform any better with four cores compared to two (this
is still largely the case today, though less so). So, most users opted for the
better performing dual cores from Intel, and professionals and hardcore enthusiasts
who could afford the best went with Core 2 Quad.

AMD would eventually get their Phenom X4's up to 2.6GHz at the cost of even
higher power consumption, though they still underperformed compared to Intel's
line-up. They also released a line of triple-core processors that met with very
little success. While AMD floundered, Intel kept pushing, continually cranking
out faster dual and quad core CPUs, culminating in the release of their new
Core i7 platform two months
ago.

AMD Phenom II

So here we are, at the dawn of another AMD processor launch, this one dubbed
Phenom II, code-name Deneb, and honestly we have our fingers crossed. AMD needs
a win, and the timing is perfect. Though Intel clearly has the performance crown
with their Core i7 platform, it is an expensive transition, and end-users wouldn't
mind a cheaper alternative. AMD doesn't need to have the absolute best performing
desktop chip in the world, they simply need to be competitive and cost-effective,
two characteristics with which they used to be synonymous.

AMD Phenom II X4 940 and 920 Processor Specifications:

Processor Frequency

X4 940 (Black Edition) = 3.0GHz
X4 920 = 2.8GHz

L1 Cache Sizes

64K of L1 instruction and
64K of L1 data cache per core (512KB total L1 per processor)

L2 Cache Sizes

512KB of L2 data cache per
core (2MB total L2 per processor)

L3 Cache Size

6MB (shared)

Memory Controller Type

Integrated 128-bit wide
memory controller *

Memory Controller Speed

Up to 1.8GHz with Dual Dynamic
Power Management

Types of Memory Supported

Support for unregistered
DIMMs up to PC2 8500 (DDR2-1066MHz)

Memory Bandwidth

Up to 17.1GB

HyperTransport 3.0 Link

One 16-bit/16-bit link @
up to 3.6GHz full duplex (1.8GHz x2)

HyperTransport 3.0 Bandwidth

Up to 14.4GB/s

Total Processor Bandwidth

Up to 31.5 GB/s total bandwidth

Packaging

Socket AM2+ 940-pin organic
micro pin grid array (micro-PGA)

Fab location

Fab 36 wafer fabrication
facilities in Dresden, Germany

Process Technology

45-nanometer DSL SOI (silicon-on-insulator)
technology

Approximate Transistor count

~ 758 million (45nm)

Approximate Die Size

258 mm2 (45nm)

Max Ambient Case Temp

62° Celsius

Nominal Voltage

0.875 - 1.5 Volts

Max TDP

125 Watts

*NOTE

MC configurable for dual
64-bit channels for simultaneous read/writes

Phenom II is an improvement over its predecessor in many ways. First off, it
is manufactured with a smaller fabrication process (45nm), allowing more circuitry
to fit on the same die. This also typically decreases power consumption and
results in higher operating frequencies. Indeed, clock speeds have received
a nice bump  the two Phenom II models released at launch, the X4 920 and
940, are clocked at 2.66GHz and 3.0GHz respectively. AMD also claims they execute
more instructions per clock cycle. L3 cache, an area Phenoms have always lacked,
has been increased significantly from 2MB to 6MB shared between the four cores.
And, finally, they have a new version of Cool'n'Quiet that has more power states
and further lowers power consumption under moderate loads.

The X4 940 Black Edition will be priced at $275USD which will more or less
match the slowest Core i7, the 920. The X4 920 meanwhile will go for $235USD.
If Phenom II can compete with Core i7, it will make a compelling choice because
of the much lower costs of the platform. Motherboards equipped with the latest
AMD 790GX chipset range between $100 and $150, while X58 Core i7 boards go for
double that. A Core i7 system also requires DDR3 memory which costs twice as
much as DDR2. Enthusiasts also have to hunt for a compatible heatsink or pay
for an adapter kit to get their current CPU heatsink mounted on a LGA1366 board.
Phenom II, on the other hand, re-uses the familiar AM2+ socket, so that's not
an issue. The 900-series model numbers of the new AMD parts seems intended to
invite comparisons (confusion?) with the Intel i7. The ploy is hardly subtle,
but perhaps obvious is what AMD marketing needs.

The AM2+ variation of Phenom II will most likely be a transitional product,
as we are on the eve of AM3's debut. Phenom II for AM3 will support DDR3 memory,
with the performance boost that comes with higher speed memory. The X4 920/940
may simply be a parting gift for those with AM2+ motherboards, rather than a
sign of things to come. If AM2+ is relegated to the budget sector as Socket
754 was during the transition to Socket 939, we probably won't see any new high-end
parts for it from here on in.